The formulation of soap bars (i.e., "toilet bars") for personal cleansing has been a matter of standard practice for many, many years. However, and irrespective of historical usage, there are still several problems associated with soap bars. As is well known to formulators and users, soap bars tend to undesirably form a type of soap/water gel, especially when stored in-use under circumstances where they can be contacted by water, e.g., in soap dishes, and the like, typically used in home lavatories. The bar then softens and smears. Besides being unsightly, this leads to wastage of the bar, in-use. One method of decreasing bar smear is by reducing the water content of the soap bar. However, reducedwater content soap bars tend to crack on storage. In addition, soap bars for personal hygiene use desirably have high lathering properties. Inappropriately adjusting the water content of otherwise standard soap bars to reduce wastage can impact negatively on lather properties. Another way to decrease soap bar wastage is to employ highly saturated (i.e., low Iodine Value) fatty acid feedstocks in the soap. However, low Iodine Value soaps lather poorly, yield bars which crack on storage and can have an undesirable gritty feel. Thus, there is a continuing search for means whereby wastage of soap bars can be diminished so that the consumer is not left with the impression that soap bar usage is uneconomical, yet without otherwise negatively affecting lather properties, cleansing performance and other desirable aspects of the bars.
It is an object of the present invention to provide soap bars having low smear, appropriate bar hardness with associated decreased wastage, adequate, or even improved, lather properties, and low tendency to crack on storage.
The present invention employs polyhydroxy fatty acid amides in combination with water-soluble fatty acid soaps, in the manner described hereinafter, to secure the above-mentioned objects. The addition of the polyhydroxy fatty acid amides reduces the tendency of the soap bar to gel, thereby resulting in less smear and a longer-lasting bar. Furthermore, the polyhydroxy fatty acid amides boost lather and reduce bar cracking. These and other objects are secured by the invention herein, as will be seen from the following disclosures.